So what's stopping us from using the CD-UB100 with the Z series to plug in huge USB sticks or even USB HDDs?

From everything I've seen, nothing. You should be able to hook it up and have decent functionality. What I find interesting, is with an optional cable you can hook your ipod up to this device. I wonder if it navigates faster than the primary ipod adapter.

http://www.crutchfield.com/p_130CDUB100 ... ailed_info

*edit* actually, according to some of the reviews it only displays 8 characters

http://www.crutchfield.com/p_130CDUB100 ... tab=review

I can't tell though it those are screen based units or single din non-nav units. But for $30, it's worth a try.

It shows up as an external device. That is, its UI will really suck on a Z-series. That's what's stopping most people from using/suggesting it on the Z-series.